This is a really useful feature IMHO. Actually, I made a similar patch myself and was just checking whether it had already been done. As it is just a small change and no collisions with other options seem to exist, I would really like to see this included in a standard release.

Patch for sort against gnu coreutils-5.0 to sort human readable file sizes as used by `df -h' and `du -h' (e.g. 12K, 3.4M, 87G). The option -h or --human-numeric-sort is added and documented. The implementation could use some work which I'm willing to do, if you're interested.